JPH04163385A - Method for treating waste laminated paper - Google Patents

Abstract

PURPOSE:To treat the subject waste paper with excellent production efficiency using a small amount of an alkali with facilitated separation of a laminated film and fiber by adding an alkali to waste laminated paper, disintegrating the waste paper into the shape of flakes, aging the flakes, separating and removing foreign materials. CONSTITUTION:An alkali (e.g. NaOH) is added to disintegrate waste laminated paper (e.g. milk carton paper) into the shape of large flakes. The disintegrated pulp is then aged in a tower for >=30min and diluted to <=10% slurry concentration (preferably about 3%) to separate and remove foreign materials. Thereby, the objective waste paper is treated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for processing laminated waste paper laminated with various plastic films or metal foils, such as milk cartons, etc.
The present invention relates to a method for processing laminated waste paper to produce high-quality fiber for paper manufacturing.

[Conventional technology]

Conventionally, in order to process laminated waste paper (hereinafter simply referred to as raw material) into high-quality fiber for paper manufacturing, warm water and alkali such as NaOH are added to the raw material in a pulper, and the slurry is mixed at a low concentration of about 4 to 6%. Laminated films such as polyethylene films are disintegrated and discarded to obtain high-quality fibers for paper manufacturing.

As shown in FIG. 3(A), the pulper in this case is rotatably equipped with a rotor 22 near the bottom of the tub 21 that gives circulation to the raw material, and a rotor 22 with a diameter of 5 to 20 mm in diameter is provided adjacent to the rotor 22. A strainer 23 with a hole diameter of about 100 mL is provided, the lower part of the strainer 23 is used as a processing raw material chamber 24, a discharge pipe 25 is connected to the processing raw material chamber 24, and a laminate film discharger is provided with an on-off valve 26 in the lower part of the tub 21. There are 27 exit ports.

By the way, in such a pulper, as shown in FIG. 3(B), raw materials are introduced, the tub 21 is filled with water, and after adding alkali, the rotor 22 is rotated to disintegrate the laminate film and fibers for a certain period of time. , then the processed raw material is 111
``After repeating this process several times, the inside of the tub 21 was diluted and disintegrated, and the laminated film accumulated inside the tub was discarded.

As described above, conventionally, the residence time of the laminate film disintegrated in the pulper in the tub is long, and the laminate film is crushed into pieces by the rotation of the rotor 22.
It passes through the strainer 23, reaches the processing material chamber 24, and is discharged from the discharge pipe 25 together with the processing material. The shredded Lamiho film in the raw material to be processed leads to a decline in product quality and paper machine operability, so it must be removed by leading it to the foreign matter removal process, but it is difficult to remove. For this purpose, as shown in FIG. 3(A), after the raw material to be treated is once stored in a chest 28, a multi-stage screening operation using a rough screening screen 29, a fine screening screen 30, etc. is required.

[Invention or problem to be solved]

However, a large amount of laminate film is contained in the raw material, and during the raw material disintegration process in the pulper, the laminate film is increasingly broken into pieces. Moreover, as mentioned above, conventional pulpers operate in batch mode and do not operate continuously. This resulted in poor production efficiency.

The present invention solves the above-mentioned conventional problems, facilitates the separation of the laminated film and fibers, prevents the lamination film from being fragmented as much as possible, simplifies the subsequent screening process, and enables continuous operation. The object of the present invention is to provide a method for processing laminated waste paper that can improve production efficiency.

[Means to solve the problem]

The present invention is a laminate characterized by adding an alkali to laminated waste paper to disintegrate it into large flakes, aging it in a tower for 30 minutes or more, and then diluting the slurry to a concentration of 10% or less to separate and remove foreign substances. This is a waste paper processing method.

[For production]

The operation of the present invention will be explained below with reference to the drawings showing one embodiment thereof.

In Figure 1, raw materials such as milk cartons are disintegrated by a disintegrating device 1.
Add an alkali such as NaOH, and if necessary, supply hot water at about 50°C to make a slurry with a concentration of 30%.
As mentioned above, preferably at a concentration of 35 to 40%, it is disintegrated into large flakes and odor is removed.

The disintegrating device 1 includes, for example, a drum 2 that has an inlet at the upper end and an outlet at the lower end, and is tilted and rotated by a motor A.
A rotary shaft 4 having a disintegrating protrusion 3 coaxially rotated by a motor B in the opposite direction to the rotational direction of the drum 2 is disposed inside, and the disintegration can be performed at a high concentration of 30% or more. The type shown in Japanese Patent No. 24374 is preferred.

In this disaggregation process, alkali is added directly to the raw material of Habo-dry, so a small amount of alkali is added and the alkali is absorbed well.
The laminate film is easily peeled off, and coarse laminate films can be peeled off in a short time.

The raw material from which the coarse laminate film has been removed in the disintegrating device 1 is transferred by a conveyor 5 into a ripening tower 7 equipped with a stirring impeller 6 at the bottom, where it is aged while being stirred. The aging time should be at least 30 minutes,
The longer the time, the better, or about 30 minutes to 24 hours, so that the remaining laminate film and fibers can be easily disintegrated.

The raw material aged in the aging tower 7 is reduced in concentration to 1 with dilution water.
It is diluted to 0% or less, preferably about 3%, and transferred to the foreign matter separator 8. The foreign material separator 8 can be a rotating drum screen with hydrofoil or a 6 to 8 m
Equipped with a circular strainer with mφ round holes and a rotating impeller shaped like a hydrofoil to prevent clogging of this strainer, a strainer with extremely low crushing action is used to break the remaining foreign matter into small pieces. It is possible to disaggregate the fibers and complete the rough sorting without having to do anything.

Therefore, the raw material sent to the CHEST 9 has already undergone disintegration and rough selection, and can be directly sent to the selection screen 1° for selection to obtain high-quality fibers for paper manufacturing.

〔Effect of the invention〕

As mentioned above, the present invention involves adding alkali to laminated waste paper to disintegrate it into large flakes, aging it in a tower for 30 minutes or more, and then diluting the slurry to a concentration of 10% or less to separate and remove foreign substances. This reduces the amount of alkali used, makes it easy to separate the laminate film and fibers, and simplifies the screening process by preventing the laminate film from breaking into pieces. Furthermore, continuous operation is possible, increasing production efficiency. It has extremely beneficial effects, such as being able to improve

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing one embodiment of the present invention;
The figure is a structural diagram of an example of the device used in the present invention, and Figure 3 (
8) is a conventional processing system diagram, and Figure 3 (B) is Figure 3 (A).
This is a flow sheet of the main processes inside. l Disintegration device, 2-...1 ram, 3. Projection piece for disintegration,
4. Rotating shaft, 5... Conveyor, 6. Stirring impeller, 7. Aging group, 8.. Foreign matter separator, 9. Chess 1~.
10 ・Selection screen, 21 tab, 22 rotor,
23 strainer, 24 processing raw material chamber, 25/discharge pipe,
2G... Opening/closing valve, 27... Laminate film deodorizing port, 28 Chiest, 29... Rough selection screen, 3
0... Carefully selected screen.

Claims (1)

[Claims] (1) A laminated waste paper characterized by adding alkali to the laminated waste paper and disintegrating it into large flakes, aging it in a tower for 30 minutes or more, and then diluting the slurry to a concentration of 10% or less to separate and remove foreign substances. Processing method.